Benchmark: filter X findIndex

Script Preparation code:

window.testList = [
  { a: 'one', b: 1},
  { a: 'two', b: 2},
  { a: 'three', b: 3},
  { a: 'four', b: 4},
  { a: 'five', b: 5},
  { a: 'six', b: 6}
];

Tests:

filter
const resultFilter = window.testList.filter(({ a }) => a === 'four'); const firstMatch = resultFilter[0];
findIndex
const resultFilter = window.testList.findIndex(({ a }) => a === 'four'); const firstMatch = window.testList[resultFilter[0]];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
filter
findIndex

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

**Benchmark Explanation**

The provided JSON represents a JavaScript microbenchmark, which is a small program designed to measure the performance of specific code snippets. The benchmark is designed to test two approaches: filtering and using `findIndex` on an array.

**Filter Approach**

In this approach, we have a simple array `testList` containing objects with two properties: `a` (a string) and `b` (an integer). We create a new constant `resultFilter` by applying the `filter()` method to `testList`, which returns a new array containing only the elements that satisfy the condition `{ a } === 'four'`.

The benchmark measures the performance of this approach by:

* Creating an execution plan with a large number of iterations (not shown in the provided code)
* Running each iteration and measuring the time taken
* Repeating this process 1,000 times to get an average execution time

**FindIndex Approach**

In this approach, we have the same `testList` array. We create another constant `resultFilter` by applying the `findIndex()` method to `testList`, which returns the index of the first element that satisfies the condition `{ a } === 'four'`.

The benchmark measures the performance of this approach in two ways:

* Directly indexing into `testList` using the returned index (`window.testList[resultFilter[0]]`)
* Using the property accessor syntax (`resultFilter[0]`) to access the value at that index

**Comparison**

Both approaches have their pros and cons:

* **Filter Approach**
	+ Pros:
		- More efficient, as it avoids iterating over all elements in the array
		- Can be used with other filtering conditions using the same syntax
	+ Cons:
		- May create a new array, which can consume memory if `resultFilter` is large
* **FindIndex Approach**
	+ Pros:
		- More efficient, as it avoids creating a new array and only accesses existing elements
	+ Cons:
		- Requires using index arithmetic or property accessor syntax, which may be slower in some cases

**Library**

In this benchmark, the `Array.prototype.filter()` and `Array.prototype.findIndex()` methods are used. These methods are part of the ECMAScript standard library and are implemented by most modern browsers.

**Special JavaScript Feature/Syntax**

None mentioned in this benchmark.

**Alternatives**

If you need to filter or find an element in an array, you can consider using other approaches:

* Using `Array.prototype.every()`, `Array.prototype.some()`, or `Array.prototype.forEach()` instead of `filter()`
* Using `Array.prototype.indexOf()` instead of `findIndex()`
* Using a custom implementation with loops and conditional statements

Keep in mind that the best approach depends on your specific use case, performance requirements, and compatibility constraints.

Related benchmarks:

filter X findIndex (version: 0)

filter X findIndex

Comparing performance of: filter vs findIndex

Created: 4 years ago by: Guest

Jump to the latest result

filter

findIndex

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):